Technical Field
The following disclosure relates to detection of the presence or absence of air in a hydraulic braking system.
Description of the Related Art
Patent Document 1 (Japanese Patent Application Publication No. 2013-208987) and Patent Document 2 (Japanese Patent Application Publication No. 2014-213755) disclose hydraulic braking systems including: a master cylinder; a rearward-hydraulic-pressure controller connected to a rearward chamber formed behind a pressurizing piston in the master cylinder; and a brake cylinder connected to a pressure chamber formed in front of the pressurizing piston. The rearward-hydraulic-pressure controller includes: a high pressure source including a pump device and an accumulator; and a regulator configured to use a hydraulic pressure produced by the high pressure source to control a hydraulic pressure in an output chamber to a hydraulic pressure having a magnitude related to a hydraulic pressure in an input chamber. Patent Document 2 discloses an air detector configured to detect the presence or absence of air in the rearward-hydraulic-pressure controller based on a hydraulic pressure in the accumulator. The pump device is driven after air bleeding. In the case where the hydraulic pressure in the accumulator when a set length of time is elapsed is lower than a determination threshold value, it is determined that air exists.